During the Second World War, Winston Churchill gave General Alexander a job description for the destruction of the German army.  Handwritten, all on one page, it read as follows:

1.  Your prime and main duty will be to take on or destroy at the earliest opportunity the German-Italian army commanded by Field Marshal Rommel together with all its supplies and establishments in Egypt and Libya.

2.  You will discharge or cause to be discharged such other duties as pertain to your command, without prejudice to the task described in paragraph 1 which must be considered paramount in His Majesty's interests.

You will note that he did not tell Alexander where or how to deploy his armour or to take care that artillery was carefully aimed, but took care in the second paragraph to make sure  the General could not use one requirement to duck his other responsibilities

A more familiar way  to write a job description is to summarize what the incumbent is responsible for and then to go into great detail as to how the incumbent must implement these responsibilities.

This is the type of job description written for a bureaucracy, and is the preferred style for federal, provincial and municipal governments.  The position description is used for purposes such as advertising the post, negotiation with unions, classification, determining pay scales, and so on.

The incumbent is evaluated on the basis of the individuals ability to perform in relation to this detailed statement of work.  In fact, performance evaluation forms are often based on this type of detailed instruction and thinking. What happens with job descriptions like this is that the incumbent feels mandated to meet the details, but no more, and the description becomes the parameter of the position.

When writing a job description it might be a good idea to consider Winston Churchill's methodology.  If you wish to give the incumbent opportunity and encouragement to exercise creativity and innovation the job description should include what you wish the incumbent to achieve in clear and simple terms in the same way that Churchill included the other duties of Alexander's command.

This of course does not preclude  including a more detailed description of expected performance and results.

As you may know from earlier experience a job description must include enough information that the incumbent and the employer are both clear as to exactly what is expected so that the employer can point out where the conduct of the employee is not meeting expectations.

This can be achieved by carefully stating the duties of the position as expectations rather than as mandatory responsibilities, that is to say, the results rather than the method.  If this can be done it allows the incumbent to demonstrate creativity and initiative within the bounds of the job description.

If you are writing or rewriting a job description now or in the near future why not try Churchill's method?  You and your employee might find it very well worthwhile.